US6065349A - Prestressed annular acoustic transducer - Google Patents

Prestressed annular acoustic transducer Download PDF

Info

Publication number
US6065349A
US6065349A US08/860,223 US86022397A US6065349A US 6065349 A US6065349 A US 6065349A US 86022397 A US86022397 A US 86022397A US 6065349 A US6065349 A US 6065349A
Authority
US
United States
Prior art keywords
annulus
tightening
keys
sectors
shaper
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US08/860,223
Other languages
English (en)
Inventor
Marc Edouard
Bernard Loubieres
Pascal Bocquillon
Olivier Lacour
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Thales SA
Original Assignee
Thomson CSF SA
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Thomson CSF SA filed Critical Thomson CSF SA
Assigned to THOMSON-CSF reassignment THOMSON-CSF ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: BOCQUILLON, PASCAL, EDOUARD, MARC, LACOUR, OLIVIER, LOUBIERES, BERNARD
Application granted granted Critical
Publication of US6065349A publication Critical patent/US6065349A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B06—GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS IN GENERAL
    • B06B—METHODS OR APPARATUS FOR GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS OF INFRASONIC, SONIC, OR ULTRASONIC FREQUENCY, e.g. FOR PERFORMING MECHANICAL WORK IN GENERAL
    • B06B1/00—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency
    • B06B1/02—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy
    • B06B1/06—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy operating with piezoelectric effect or with electrostriction
    • B06B1/0644—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy operating with piezoelectric effect or with electrostriction using a single piezoelectric element
    • B06B1/0655—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy operating with piezoelectric effect or with electrostriction using a single piezoelectric element of cylindrical shape

Definitions

  • the present invention relates to piezoelectric transducers taking the form of an annulus and which are fitted with means making it possible to prestress this annulus so as to apply a stress of specified value thereto. It also relates to the processes which make it possible to implement these means for applying the said prestress to the annulus.
  • a particular form of such a transducer is that of a torus of rectangular cross-section, formed by a set of ceramic segments polarized head-to-tail and assembled by adhesive bonding with the interposition of an electrode between each segment.
  • the segments thus excited contract and expand in tempo with the electrical signals which are applied by the electrodes, and this tangential motion of the segments translates into a radial extension and contraction of the annulus. This motion therefore gives rise to the production of acoustic waves which are emitted with radial symmetry about the axis of the annulus into the medium, generally the sea, in which the transducer is immersed.
  • the annuli are subjected to piezoelectric stresses of high amplitude and this effect is all the more marked the lower the frequency of the acoustic waves to be emitted.
  • the annulus would tend to break up, initially at the interfaces between the various segments and subsequently by straightforward rupture of the piezoelectric ceramics above a certain emission level.
  • prestress the annulus by compressing it with the aid of means which apply radial forces thereto, directed towards the centre and distributed uniformly over the outside surface of the annulus.
  • These radial stresses induce tangential stresses which tend to hold the segments together securely and oppose the development within the ceramics of tensile stresses to which this type of material is known to be particularly brittle.
  • the invention proposes a prestressed annular acoustic transducer, of the type comprising a set of piezoelectric segments arranged in the form of an annulus, principally characterized in that its segments are grouped to form substantially identical sectors, and in that it furthermore comprises end pieces fixed to the ends of these sectors in order to delimit wedge-shaped gaps between them, the narrower end of the wedge pointing towards the inside of the annulus, wedge-shaped tightening keys matched to these gaps and placed in them, a shaper annulus making it possible to hold the set of sectors, and tightening means allowing the tightening keys to be made to slide towards the inside of the annulus in order to prestress the segments by the shaper annulus.
  • the transducer furthermore comprises strain gauges fixed to the inside face of the sectors to allow measurement of the stresses applied to the segments.
  • the tightening means are formed by screws fixed in holes made in the inner face of the tightening keys and fitted with washers which bear on the end pieces of the sectors so as to allow a tension to be exerted on the keys when the screws are screwed.
  • the gaps remaining on the one hand between the tightening keys and the shaper annulus and on the other hand between these same tightening keys and the tightening means are plugged with a filler product when adjustment is effected.
  • the dynamic stiffness of the shaper annulus is substantially ten times smaller than that of the piezoelectric segments.
  • the invention furthermore proposes a process for adjusting such a transducer principally characterized in that the tightening means are progressively tightened while monitoring the readings given by the strain gauges so as to obtain identical stresses equal to the desired value on each sector.
  • FIG. 1 an isometric perspective view of an annular transducer according to the invention
  • FIG. 2 an isometric perspective view of a wedge for adjusting this annulus
  • FIG. 3 an isometric perspective view of a sector of the annulus lying between two wedges such as those of FIG. 2.
  • the piezoelectric annulus forming the transducer is made by assembling a set of elementary segments 101 having the shape of prisms of trapezoidal cross-section entirely similar to those used in the prior art.
  • the annulus is divided into a set of substantially identical sectors 102 joining together subsets of segments.
  • the diameter of the annulus is of the order of 20 cm and it is divided into 5 sectors each including 8 segments.
  • FIG. 3 Represented in FIG. 3 is one of these sectors in isolation. It is formed of 8 elementary segments 101 made of piezoelectric ceramic, PZT for example. These segments are adhesively bonded together with the interposition of electrodes 103 which allow the application of the electrical excitation voltages. According to a known technique, the segments are tangentially polarized alternately in opposite directions. The electrodes 103 are joined alternately to connections 104 and 105 which enable these electrical voltages to be applied to the electrodes.
  • ends of the sector are fitted with metal pieces adhesively bonded to the outside faces of the endmost segments.
  • These metal pieces are wedge-shaped and their outside lateral faces make an angle ⁇ with the direction of the radius of the annulus, as represented in FIG. 1.
  • This angle a is such that the width of the wedge is greater over the inside surface of the annulus than over its outside surface.
  • At least one strain gauge 107 is furthermore arranged on the inside face of the sector, this making it possible to measure the stresses applied to the sectors at this inside face.
  • This strain gauge is for example made in the known form of a film supporting metal electrodes arranged in such a way that the extension or contraction of the surface on which the gauge is adhesively bonded causes a variation in the resistance of these electrodes according to a known law.
  • the set of 5 sectors is arranged inside a shaper annulus 108 which makes it possible to define the shape and the dimensions of the piezoelectric annulus.
  • This annulus is for example manufactured from epoxy glass with a carefully polished inside surface.
  • Adjuster keys having the shape of wedges 109 fill this clearance.
  • These keys are therefore placed between the sectors and enable these sectors to be locked inside the shaper annulus 108.
  • the angle between the two lateral faces of these keys is designed to correspond to the angle alpha of the end pieces of the sectors, so that when the keys are in position these outside faces are applied to the outside faces of these end pieces with as small an angular clearance as possible, so as to avoid excessive stresses at the points of contact between the keys and the end pieces.
  • the faces of the keys 109 oriented towards the inside of the annulus are furnished with tapped holes 110, here 3 in number, which make it possible to receive tightening members which are screwed into these holes while bearing on the faces of the end pieces 106 themselves oriented towards the inside of the annulus.
  • These tightening pieces may be more or less complicated, but in the example embodiment represented they are composed of screws 111 on which washers 112 are threaded. These screws are screwed into the tapped holes, then onto the washers, themselves bearing on the pieces 106.
  • a tension is thus exerted on the wedge-shaped keys 109 towards the inside of the annulus and this tends, given the angles ⁇ , to part the sectors 101 and to enlarge the annulus formed by the set of these sectors and keys.
  • the piezoelectric annulus is brought to bear firmly on the inside of the shaper annulus 108, thereby, firstly, holding the set of pieces in position.
  • the invention proposes to use the strain gauges 107 described earlier.
  • the latter will be linked to measurement means 113 which make it possible to determine the stress at these gauges.
  • the stress at the locations or [sic] these gauges are placed indicates, to within a known multiplier coefficient, the overall stress applied to the ceramics forming each sector.
  • the sectors are sufficiently small for the stresses thus obtained and measured to be uniformly distributed. In the case of a larger annulus, it would perhaps be expedient to use a greater number of sectors.
  • the tightening of the screws will be carried out progressively while continuously checking the change in the stresses, so as to obtain the desired overall stress and to minimize as far as possible the discrepancies between the stresses which is [sic] measured locally.
  • the gap e between the keys 109 and the shaper annulus 108 can perhaps be filled as can any residual gap between the tightening means and these same keys, with a filler material.
  • This filler material will preferably be relatively elastic, polyurethane for example, so as to be able to allow possible subsequent fine-tuning.
  • shaper annulus 108 affects the acoustic characteristics of the transducer thus constructed, as is anyway the case in the other already known prestressing systems. It has been determined that in order to obtain correct results, in particular which do not excessively disturb the operation of the piezoelectric annulus, it was preferable to use a shaper annulus whose dynamic stiffness is around ten times smaller than that of the piezoelectric annulus made of ceramics.
  • this device As compared with the known systems for prestressing, this device is particularly easy to implement and hence inexpensive. Furthermore, it is modular and this makes it possible, as the case may be, to replace just a single segment in the event of a fault therein. The stresses are distributed in a remarkably uniform manner, and their variations over time is [sic] very small. It is entirely possible to fine-tune this prestress, either as a function of the operational conditions, or in order to correct drifting over time. Moreover the assembly is dismantleable, thus allowing the repairs mentioned earlier. Lastly, the metal pieces 106 and 109 promote, as the case may be, heat sinkage, especially when the annulus is loaded with very high electrical powers.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Measuring Fluid Pressure (AREA)
  • Piezo-Electric Transducers For Audible Bands (AREA)
  • Transducers For Ultrasonic Waves (AREA)
US08/860,223 1994-12-23 1995-12-15 Prestressed annular acoustic transducer Expired - Lifetime US6065349A (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
FR9415587 1994-12-23
FR9415587A FR2728755B1 (fr) 1994-12-23 1994-12-23 Transducteur acoustique en anneau precontraint
PCT/FR1995/001676 WO1996020046A1 (fr) 1994-12-23 1995-12-15 Transducteur acoustique en anneau precontraint

Publications (1)

Publication Number Publication Date
US6065349A true US6065349A (en) 2000-05-23

Family

ID=9470196

Family Applications (1)

Application Number Title Priority Date Filing Date
US08/860,223 Expired - Lifetime US6065349A (en) 1994-12-23 1995-12-15 Prestressed annular acoustic transducer

Country Status (7)

Country Link
US (1) US6065349A (ja)
EP (1) EP0799097B1 (ja)
JP (1) JP3653733B2 (ja)
AU (1) AU695815B2 (ja)
DE (1) DE69505014T2 (ja)
FR (1) FR2728755B1 (ja)
WO (1) WO1996020046A1 (ja)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6345014B1 (en) * 1998-03-10 2002-02-05 Thomson Marconi Sonar S.A.S. Collapsible annular acoustic transmission antenna
US20060213277A1 (en) * 2003-01-17 2006-09-28 Peter Tschanz Prestressing element for sensors
US8854923B1 (en) * 2011-09-23 2014-10-07 The United States Of America As Represented By The Secretary Of The Navy Variable resonance acoustic transducer
US10379207B2 (en) * 2013-12-20 2019-08-13 Thales Compact omnidirectional antenna for dipping sonar

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2826828B1 (fr) 2001-06-29 2003-12-12 Thomson Marconi Sonar Sas Transducteur acoustique a anneau precontraint
CN109633614B (zh) * 2018-11-29 2023-08-01 哈尔滨工程大学 一种低后辐射高频换能器线阵

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3043967A (en) * 1960-01-13 1962-07-10 Walter L Clearwaters Electrostrictive transducer
US3230505A (en) * 1963-06-27 1966-01-18 David E Parker Reinforced ceramic cylindrical transducers
US4313510A (en) * 1980-11-24 1982-02-02 General Electric Company Weighing scale with dynamic zero error correction
US4546459A (en) * 1982-12-02 1985-10-08 Magnavox Government And Industrial Electronics Company Method and apparatus for a phased array transducer

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3542741A1 (de) * 1985-12-03 1987-06-04 Taga Electric Co Ltd Torsionsschwingungseinrichtung
GB9409133D0 (en) * 1994-05-09 1994-11-30 Secr Defence Sonar ring transducer

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3043967A (en) * 1960-01-13 1962-07-10 Walter L Clearwaters Electrostrictive transducer
US3230505A (en) * 1963-06-27 1966-01-18 David E Parker Reinforced ceramic cylindrical transducers
US4313510A (en) * 1980-11-24 1982-02-02 General Electric Company Weighing scale with dynamic zero error correction
US4546459A (en) * 1982-12-02 1985-10-08 Magnavox Government And Industrial Electronics Company Method and apparatus for a phased array transducer

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6345014B1 (en) * 1998-03-10 2002-02-05 Thomson Marconi Sonar S.A.S. Collapsible annular acoustic transmission antenna
US20060213277A1 (en) * 2003-01-17 2006-09-28 Peter Tschanz Prestressing element for sensors
US7500398B2 (en) * 2003-01-17 2009-03-10 Kistler Holding, Ag Prestressing element for sensors
US8854923B1 (en) * 2011-09-23 2014-10-07 The United States Of America As Represented By The Secretary Of The Navy Variable resonance acoustic transducer
US10379207B2 (en) * 2013-12-20 2019-08-13 Thales Compact omnidirectional antenna for dipping sonar

Also Published As

Publication number Publication date
EP0799097A1 (fr) 1997-10-08
FR2728755A1 (fr) 1996-06-28
AU4393496A (en) 1996-07-19
JP3653733B2 (ja) 2005-06-02
WO1996020046A1 (fr) 1996-07-04
DE69505014D1 (de) 1998-10-29
FR2728755B1 (fr) 1997-01-24
DE69505014T2 (de) 1999-05-06
AU695815B2 (en) 1998-08-20
JPH10511523A (ja) 1998-11-04
EP0799097B1 (fr) 1998-09-23

Similar Documents

Publication Publication Date Title
US3368085A (en) Sonic transducer
US5739625A (en) Segmented ring transducers
US2558563A (en) Piezoelectric strain gauge
Fuller et al. Experiments on active control of sound radiation from a panel using a piezoceramic actuator
US2900536A (en) Design of electro-mechanical transducer elements
US4051455A (en) Double flexure disc electro-acoustic transducer
US5345428A (en) Flextensional transducers
US3101419A (en) Electromechanical transducer system
US4764907A (en) Underwater transducer
US3043967A (en) Electrostrictive transducer
US6065349A (en) Prestressed annular acoustic transducer
CN111323317B (zh) 一种基于压电双叠堆共振驱动的高频疲劳试验装置及方法
US5995453A (en) Composite ultrasonic transducer
US5793148A (en) Arrangement in a drive unit for an ultrasound sealing unit
US4220886A (en) Electroacoustic sandwich transducer with bonded joints
US4130624A (en) Piezo-electric disc mounting methods and apparatus
US4446396A (en) Ultrasonic transducer with Gaussian radial pressure distribution
EP0492882B1 (en) Moment bender transducer drive
US5007030A (en) Transducer assembly for deep submergence
Rosen et al. Transverse vibrations of compressed annular plates
SU1045014A1 (ru) Датчик силы
US5204844A (en) Moment bender transducer
House Jr Maximum power criterion for the vibrating free edge disk
Tressler et al. Thin, Low Frequency, High Displacement Actuator Panels
JPH10315334A (ja) 超音波加工装置

Legal Events

Date Code Title Description
AS Assignment

Owner name: THOMSON-CSF, FRANCE

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:EDOUARD, MARC;LOUBIERES, BERNARD;BOCQUILLON, PASCAL;AND OTHERS;REEL/FRAME:008710/0759

Effective date: 19970522

STCF Information on status: patent grant

Free format text: PATENTED CASE

FPAY Fee payment

Year of fee payment: 4

FPAY Fee payment

Year of fee payment: 8

FPAY Fee payment

Year of fee payment: 12